Utskrift
Blant insekter, midd og snegl har vi både SKADE- og NYTTEDYR. De omtales gjerne som SKADEDYR når de angriper planter som vi dyrker til mat, fôr eller som prydplanter. Videre omtales de som NYTTEDYR når de dreper skadedyr eller når de hjelper til med pollinering av planter. Insekter kan også brukes som protein og fettkilde i fôr til husdyr og som mat til mennesker.
Ingeborg Klingen
Avdelingsleder/forskningssjef
-
Divisjon for bioteknologi og plantehelse
(+47) 930 92 211 ingeborg.klingen@nibio.no Kontorsted: Ås - Bygg H7
NIBIO har den største samlede fagkompetansen innen insekter, midd og snegl som skade- og nyttedyr i Norge. Vi utfører forsknings-, utviklings- og innovasjonsarbeid innen overvåking, biologi og bekjempelse av skadedyr i landbruk, skogbruk, planteskoler, juletrefelt og grøntarealer».
Arbeidet ved NIBIO fokuserer for tiden på følgende temaer:
Planteklinikken ved NIBIO er et diagnoselaboratorium som tilbyr identifisering av ulike organismer som er skadelige for planter. Riktig diagnose danner grunnlag for å vurdere riktige tiltak mot skadegjøreren.
Mer informasjon Til tjenestenPlantevernguiden er en nettbasert tjeneste som gir deg en samlet oversikt over godkjente kjemiske og biologiske plantevernmidler. Tjenesten er utviklet i et samarbeid mellom Mattilsynet og NIBIO.
Mer informasjon Til tjenestenNettside med nyttig og relevant informasjon om biologi og bekjempelse av planteskadegjørere (ugras, sykdommer og skadedyr). Du finner også informasjon om biologien til en del nyttedyr av plantevernbetydning.
Mer informasjon Til tjenestenVarsling innen planteskadegjørere
Mer informasjon Til tjenestenAlthough it is well known that insects are sensitive to temperature, how they will be affected by ongoing global warming remains uncertain because these responses are multifaceted and ecologically complex. We reviewed the effects of climate warming on 31 globally important phytophagous (plant‐eating) insect pests to determine whether general trends in their responses to warming were detectable. We included four response categories (range expansion, life history, population dynamics, and trophic interactions) in this assessment. For the majority of these species, we identified at least one response to warming that affects the severity of the threat they pose as pests. Among these insect species, 41% showed responses expected to lead to increased pest damage, whereas only 4% exhibited responses consistent with reduced effects; notably, most of these species (55%) demonstrated mixed responses. This means that the severity of a given insect pest may both increase and decrease with ongoing climate warming. Overall, our analysis indicated that anticipating the effects of climate warming on phytophagous insect pests is far from straightforward. Rather, efforts to mitigate the undesirable effects of warming on insect pests must include a better understanding of how individual species will respond, and the complex ecological mechanisms underlying their responses.
1. Due to globalisation, trade and transport, the spread of alien species is increasing dramatically. Some alien species become ecologically harmful by threatening native biota. This can lead to irreversible changes in local biodiversity and ecosystem functioning, and, ultimately, to biotic homogenisation. 2. We risk-assessed all alien plants, animals, fungi and algae, within certain delimitations, that are known to reproduce in Norway. Mainland Norway and the Arctic archipelago of Svalbard plus Jan Mayen were treated as separate assessment areas. Assessments followed the Generic Ecological Impact Assessment of Alien Species (GEIAA) protocol, which uses a fully quantitative set of criteria. 3. A total of 1519 species were risk-assessed, of which 1183 were species reproducing in mainland Norway. Among these, 9% were assessed to have a severe impact, 7% high impact, 7% potentially high impact, and 49% low impact, whereas 29% had no known impact. In Svalbard, 16 alien species were reproducing, one of which with a severe impact. 4. The impact assessments also covered 319 so-called door-knockers, i.e. species that are likely to establish in Norway within 50 years, and 12 regionally alien species. Of the door-knockers, 8% and 10% were assessed to have a severe and high impact, respectively. 5. The impact category of most species was driven by negative interactions with native species, transformation of threatened ecosystems, or genetic contamination. The proportion of alien species with high or severe impact varied significantly across the different pathways of introduction, taxonomic groups, time of introduction, and the environments colonised, but not across continents of origin. 6. Given the large number of alien species reproducing in Norway and the preponderance of species with low impact, it is neither realistic nor necessary to eradicate all of them. Our results can guide management authorities in two ways. First, the use of quantitative assessment criteria facilitates the prioritisation of management resources across species. Second, the background information collected for each species, such as introduction pathways, area of occupancy and ecosystems affected, helps designing appropriate management measures.
BACKGROUND Pollen beetles are key pests in oilseed rape (OSR) production. These beetles use visual and olfactory cues to locate their host plants at specific phenological stages, hence trap cropping may represent an alternative pest control strategy. In this study, a trap crop strategy for spring OSR was developed. To elaborate such a trap cropping system, a pest control measure that eradicates the attracted beetles in the trap crop before they migrate further into the main crop was included in the final trap cropping strategy. RESULTS Testing yellow‐flowering turnip rape and one yellow‐ and two cream‐coloured flowering OSR cultivars as potential crops in different trap cropping strategies, we found that pollen beetles clearly preferred turnip rape over the cream‐coloured and yellow OSR cultivars, and preferred the yellow OSR cultivar over the two cream‐coloured cultivars. This behaviour was related to the plant growth stage and associated volatile and colour signals of the tested cultivars. Using turnip rape as a trap crop and testing kairomone‐ or insecticide‐assisted trap cropping as the pest control strategy was as effective as compared with whole fields treated with a standard pesticide. CONCLUSION Combining a turnip rape cultivar as trap crop with kairomone traps placed in the trap crop as a killing agent may enable renunciation of pesticides in spring OSR production. © 2020 Society of Chemical Industry
The invasive slug Arion vulgaris (Gastropoda: Arionidae) is an agricultural pest and serious nuisance in gardens of Central and Northern Europe. To investigate if the success of A.vulgaris in Norway can be attributed to a release from parasites, we compared the prevalence and parasite load of nematodes and trematodes in A. vulgaris to that of three native gastropod species, A. circumscriptus, A. fasciatus and Arianta arbustorum, in SE Norway. We found A. vulgaris to have the highest prevalence of both parasite groups (49% nematodes, 76% trematodes), which does not support the parasite release hypothesis, but rather points to A. vulgaris as a potentially important intermediate host of these parasites. For trematodes the number of individuals (parasite load) did not differ among host species; for nematodes it was higher in A. vulgaris than A. fasciatus. To further compare the parasite susceptibility of the surveyed gastropods, we exposed A. vulgaris, A. fasciatus, and A. arbustorum to a slug parasitic nematode, Phasmarhabditis hermaphrodita, in the laboratory. This nematode is commercially available and widely used to control A. vulgaris. The non-target species A. fasciatus was most affected, with 100% infection, 60% mortality and significant feeding inhibition. A. vulgaris was also 100% infected, but suffered only 20% mortality and little feeding inhibition. The load of P. hermaphrodita in infected specimens was not significantly different for the two Arion species (median: 22.5 and 45, respectively). Only 35% of A. arbustorum snails were infected, none died, and parasite load was very low (median: 2). However, they showed a near complete feeding inhibition at highest nematode dose, and avoided nematode-infested soil. Our results indicate that A. vulgaris may be less susceptible to P. hermaphrodita than the native A. fasciatus, and that non-target effects of applying this nematode in fields and gardens should be further investigated.
1 Ips amitinus arrived in Northern Europe at the beginning of 1900s, although its recent expansions to the northernmost conifers have been rapid. 2 Analyses of recent records, MaxEnt models and regional population size estimates are used to discuss its peculiar range shifts and potential as a forest pest in Northern Europe. 3 Ips amitinus was probably absent in northern glacial refugia for Norway spruce in the Russian plain and northward expansions from its glacial refugia in the Central European mountains may have been slowed down by: (i) ecological barriers of post-glacial dry plains and bogs in Central Europe; (ii) heavy utilization of conifers; and (iii) Allee effects as a result of fragmented forests and an unfavourable climate for a cold-adapted species in the continental lowlands. 4 MaxEnt models predict that I. amitinus may become widespread in the Northern European forests, whereas its populations in the southernmost mountain ranges of Europe may decline in the future. 5 The population levels of I. amitinus in recently invaded northern areas are still lower than those in core areas of Central Europe, although the population development in Central Europe indicates that future bark beetle outbreak periods may boost the I. amitinus populations in Northern Europe as well.
Sentinel plants, plants in exporting countries that are inspected at regular intervals for signs and symptoms of invertebrate pests and microbial pathogens, are a promising tool for detecting and identifying harmful organisms of woody plants prior to their introduction into importing countries. Monitoring of sentinel plants reveals crucial information for pest risk analyses and the development of mitigation measures. The establishment of sentinel plants requires the import and plantation of non-native plants, which may be affected by the laws, regulations and administrative procedures in the individual countries. To evaluate the feasibility of sentinel plants as a global approach, this study aimed to summarise regulations and administrative procedures that affect the establishment of sentinel plants using non-native plants in countries worldwide. Information about national regulations of import and planting of non-native plant species was collected through a questionnaire survey, conducted among national representatives to the International Plant Protection Convention. Over 40 countries responded. The results show that legislations and regulations should not be major obstacles for a global use of the sentinel plants approach. However, the few existing experiences show that it can be complicated in practice. Here we describe the current state of art of the procedures that should be adopted to establish sentinel plants and we propose a strategy to circumvent the shortcomings resulting from the lack of a specific regulation.
We present the results of an inventory and status assessment of alien species in Norway. The inventory covered all known multicellular neobiota, 2496 in total, 1039 of which were classified as naturalised. The latter constitute c. 3% of all species known to be stably reproducing in Norway. These figures are higher than expected from Norway’s latitude, which may be due a combination of climatic and historical factors, as well as sampling effort. Most of the naturalised neobiota were plants (71%),followed by animals (21%) and fungi (8%). The main habitat types colonised were open lowlands (79%), urban environments (52%) and woodlands (42%). The main areas of origin were Europe (67%), North America (15%) and Asia (13%). For most taxa, the rate of novel introductions seems to have been increasing during recent decades. Within Norway, the number of alien species recorded per county was negatively correlated with latitude and positively correlated with human population density. In the high-Arctic territories under Norwegian sovereignty, i.e. Svalbard and Jan Mayen, 104 alien species were recorded, of which 5 were naturalised.
Arion vulgaris Moquin-Tandon, 1855 is regarded as one of the 100 most invasive species in Europe. The native distribution range of this species is uncertain, but for many years, the Iberian Peninsula has been considered as the area of origin. However, recent studies indicate that A. vulgaris probably originated from France. We have investigated the genetic structure of 33 European populations (Poland, Norway, Germany, France, Denmark, Switzerland) of this slug, based on two molecular markers, mitochondrial cytochrome c oxidase subunit I (COI, mtDNA) and nuclear zinc finger (ZF, nDNA). Our investigation included published data from two previous studies, giving a total of 95 populations of A. vulgaris from 26 countries. This comprehensive dataset shows comparable haplotype diversity in Central, North and Western Europe, and significantly lower haplotype diversity in the East. All haplotypes observed in the East can be found in the other regions, and haplotype diversity is highest in the Central and Western region. Moreover, there is strong isolation by distance in Central and Western Europe, and only very little in the East. Furthermore, the number of unique haplotypes was highest in France. This pattern strongly suggests that A. vulgaris has originated from a region spanning from France to Western Germany; hence, the slug is probably alien/invasive in other parts of Europe, where it occurs. Our results indicate the necessity to cover as much of the distribution range of a species as possible before making conclusive assumptions about its origin and alien status.
In the family Orchidaceae, many species have highly specialised floral structures and floral fragrances resulting from interactions with specific pollinators. Olfactory cues are important for the moths to locate orchids at a distance, whereas visual cues are important at a closer range. In this study, we combined a portable air entrainment kit with an automated video monitoring system for collecting volatiles and observing behaviour directly around-the-clock (24 h) in the natural habitat of our target plant–arthropod system, the orchid Platanthera chlorantha and the hawkmoth Sphinx pinastri. We found that P. chlorantha was visited almost exclusively by S. pinastri. All the visits occurred after sunset, principally between sunset and midnight. Soon after midnight, visits dropped to levels recorded at sunset, then declined further towards sunrise. The period with most visits matched the peak production of the terpenoids (Z)-β-ocimene and (E)-β-ocimene. In contrast, linalool, (E)-cinnamyl alcohol and benzyl benzoate emission continued to increase beyond the period of peak visits up to sunrise. Methyl benzoate emissions declined throughout the night from a sunset peak. As temporal emission of the two volatile ocimenes from P. chlorantha flowers matches S. pinastri foraging visits to the flowers, we propose that they play a vital role in assisting hawkmoths locate their hosts. This is the first study to show correspondence in the timing of specific scent emissions in orchids and moth activity on the scale of hours.
Upon herbivory, plants release herbivore-induced plant volatiles (HIPVs), which induce chemical defenses in the plant as well as recruit natural enemies. However, whether synthetic HIPVs can be employed to enhance biological control in a cultivated crop in the field is yet to be explored. Here we show that a biodegradable formulation loaded with induced and food-signaling volatiles can selectively recruit the common green lacewing, Chrysoperla carnea, and reduce pest population under field conditions. In apple orchards, the new formulation attracted lacewing adults over a 4-week period, which correlated well with independent assessments of the longevity of the slow-release matrix measured through chemical analyses. In barley, lacewing eggs and larvae were significantly more abundant in treated plots, whereas a significant reduction of two aphid species was measured (98.9% and 93.6% of population reduction, for Sitobion avenae and Rhopalosiphum padi, respectively). Results show the potential for semiochemical-based targeted recruitment of lacewings to enhance biological control of aphids in a field setting. Further research should enhance selective recruitment by rewarding attracted natural enemies and by optimizing the application technique.
The effect of inoculation of strawberry roots by two entomopathogenic fungal isolates, Metarhizium robertsii (ESALQ 1622) and Beauveria bassiana (ESALQ 3375), on naturally occurring arthropod pests and plant diseases was investigated in four commercial strawberry fields during two growing seasons in Brazil. Three locations represented open-field production while strawberries were grown in low tunnels at the fourth location. Population responses of predatory mites to the fungal treatments were also assessed. Plants inoculated by the fungal isolates resulted in significantly fewer Tetranychus urticae adults compared to control plants at all four locations. The mean cumulative numbers ± SE of T. urticae per leaflet were: M. robertsii (225.6 ± 59.32), B. bassiana (206.5 ± 51.48) and control (534.1 ± 115.55) at the three open-field locations, while at the location with tunnels numbers were: M. robertsii (79.7 ± 10.02), B. bassiana (107.7 ± 26.85) and control (207.4 ± 49.90). Plants treated with B. bassiana had 50% fewer leaves damaged by Coleoptera, while there were no effects on numbers of whiteflies and thrips. Further, lower proportions of leaflets with symptoms of the foliar plant pathogenic fungi Mycosphaerella fragariae and Pestalotia longisetula were observed in the M. robertsii (4.6% and 1.3%)- and B. bassiana (6.1% and 1.3%)-treated plots compared to control plots (9.8% and 3.7%). No effect was seen on numbers of naturally occurring predatory mites. Our results suggest that both isolates tested may be used as root inoculants of strawberries to protect against foliar pests, particularly spider mites, and also against foliar plant pathogenic fungi without harming naturally occurring and beneficial predatory mites.
BACKGROUND Root inoculations of crop plants with beneficial fungi constitute a promising strategy for growth promotion and control of above‐ground pests and diseases. Here, strawberry roots (cultivar ‘Albion’ and ‘Pircinque’) were inoculated with 25 different Brazilian entomopathogenic fungal isolates of three genera and the effects on Tetranychus urticae oviposition and plant growth were evaluated in greenhouse experiments. RESULTS Reductions in the number of T. urticae eggs compared to control treatments were observed on both cultivars inoculated with almost all isolates. For the cultivar ‘Albion’, Metarhizium anisopliae (ESALQ 1604, ESALQ 1669), M. robertsii (ESALQ 1622, ESALQ 1635), Metarhizium sp. Indet. (ESALQ 1684) and Beauveria bassiana (ESALQ 3323) increased dry weight of roots and leaves, and fruit yield, while M. robertsii (ESALQ 1634), Metarhizium sp. Indet. (ESALQ 1637) and (ESALQ 1636) enhanced fruit yield and dry weight of leaves, respectively. For the cultivar ‘Pircinque’, M. anisopliae (ESALQ 1669) was the only isolate observed to increase dry weight of roots. CONCLUSION The results suggest that inoculation of strawberry roots with entomopathogenic fungi may be an innovative strategy for pest management above ground. Furthermore, these inoculations may also stimulate plant growth and strawberry production, but the effects depend on fungal strains and crop cultivar.
Pandora neoaphidis and Entomophthora planchoniana are widespread and important specialist fungal pathogens of aphids in cereals (Sitobion avenae and Rhopalosiphum padi). The two aphid species share these pathogens and we compare factors influencing susceptibility and resistance. Among factors that may influence susceptibility and resistance are aphid behavior, conspecific versus heterospecific host, aphid morph, life cycle, and presence of protective endosymbionts. It seems that the conspecific host is more susceptible (less resistant) than the heterospecific host, and alates are more susceptible than apterae. We conceptualize the findings in a diagram showing possible transmission in field situations and we pinpoint where there are knowledge gaps.
We determined how conidia of arthropod-pathogenic fungi on leaves affected the behavior of two predators—Orius majusculus (Hemiptera: Anthocoridae) and Phytoseiulus persimilis (Acari: Phytoseiidae)—when offered a choice between preying on two-spotted spider mites, Tetranychus urticae (Acari: Tetranychidae), in the presence or absence of infective conidia of Metarhizium brunneum (Ascomycota: Hypocreales) and Neozygites floridana (Entomophthoromycota: Neozygitaceae). The results indicate no significant relation between the presence of conidia and predator behavior. The only indication of interference is between the generalists O. majusculus and M. brunneum, with a trend towards more time spent feeding and more prey encounters turning into feeding events on leaf discs without conidia than on leaf discs with conidia. Our results show that the presence of fungal conidia does not alter the preying behavior of the predators, and using predators and fungi together is not limited by any interference between organisms in the short term.
We studied the effect of three Pandora neoaphidis isolates from one Sitobion avenae population, three temperatures, and two aphid species namely S. avenae and Rhopalosiphum padi on (i) aphid mortality, (ii) time needed to kill aphids, and (iii) aphid average daily and lifetime fecundity. A total of 38% of S. avenae and 7% of R. padi died and supported fungus sporulation. S. avenae was killed 30% faster than R. padi. Average daily fecundity was negatively affected only in S. avenae inoculated with, but not killed by, P. neoaphidis. Nevertheless, lifetime fecundity of both aphid species inoculated and sporulating with P. neoaphidis was halved compared to lifetime fecundity of surviving aphids in the control. Increased temperature resulted in higher mortality rates but did not consistently affect lethal time or fecundity. Results suggest that (i) temperature effects on virulence differ between isolates, even when obtained within the same host population, and (ii) even though an isolate does not kill a host it may reduce its fecundity. Our findings are important for the understanding of P. neoaphidis epizootiology and for use in pest-natural enemy modelling.
Green-sprouting potato seed tubers in light and elevated temperatures are vital for production in short-season climates. Using light-emitting diodes (LEDs) to inhibit sprout elongation during pre-sprouting may represent an energy-efficient alternative to traditional indoor light sources. Sprout growth inhibition and some photomorphogenic responses were therefore examined in potato cultivars exposed to LEDs of different wavelength maxima and irradiance rates. Red LED (660 nm) produced the strongest inhibition of sprout elongation at very low irradiances 10–100 nmol m−2 s−1, while far-red LED (735 nm) produced the strongest inhibition at higher irradiances. This inhibitory pattern was similar in all cultivars, although the degree of inhibition varied. The colour of sprouts and tuber skin remained etiolated under far-red LED, in contrast to LEDs between 380 and 660 nm which developed green colour intensity in an irradiance-dependent manner. Mixtures of red and far-red light, and pulses including red/far-red reversals did not produce stronger inhibition, except in some instances where total fluence was increased. Furthermore, green-sprouting under different LED colours did not seem to affect subsequent emergence and growth after planting. The current results suggest an involvement of multiple phytochromes in de-etiolation and sprout growth inhibition in seed potato tubers, which may be selectively utilised in LED-based green-sprouting in red and far-red wavelengths.
In organic plant production, nitrogen (N) availability is often a growth-limiting factor. Under such conditions, off-farm waste-derived nutrient resources may be an alternative to meet the N demand. In this study, we described a production method for a shrimp shell (SS) pellet Product and evaluated the N fertiliser effect and N recovery efficiency (NRE) in a controlled climate pot experiment with potatoes. The experiment was set up with low, medium and high N levels of SS pellets in comparison with a standard mineral fertiliser (MF) at 9°C, 15°C and 21°C. In a separate study, we examined the loss of N as N2O from SS pellets in comparison with SS powder in a 100 days incubation experiment. The results documented the possibility to formulate a fertiliser pellet product from SS, and that SS pellets were an effective N fertiliser in potato at all Growth temperatures. Nevertheless, a slightly slower development and lower tuber yields than for MF indicated a delayed N-availability from SS pellet fertiliser. NRE after use of MF was around 90%, and about 70% for the different levels of SS pellets. The incubation experiment showed a higher rate of available N for SS powder than for pellets (67% and 39%, respectively) after 100 days of incubation at constant humidity and temperature. This difference was attributed to a lower degree of dissolved materials and a higher rate of denitrification and N2O emissions for pellets than for powder, probably caused by differences in physical properties, occurrence of anoxic hotspots and higher microbial activity around and inside the SS pellets.
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A warmer climate may potentially have a strong effect on the health status of European oak forests by weakening oak trees and facilitating mass reproduction of wood boring insects. We did a laboratory experiment in Slovakia to study the response of major pest beetles of oak and their parasitoids to different temperature regimes as background for predicting climatic effects and improving management tools of European oak forests. With higher temperatures the most important oak pest Scolytus intricatus emerged much earlier, which indicate that completion of a second generation and increased damage further north in European oak forests may be possible. Lower temperatures gave longer larval galleries and more offspring per parents but still lower beetle production due to semivoltine life cycle. For buprestids and longhorn beetles warmer temperatures resulted in more emerging offspring and a shift towards earlier emergence in the same season, but no emergence in the first season indicated that a change to univoltine populations is not likely. Reduced development success of parasitoids at the highest temperatures (25/30 °C) indicates a loss of population regulation for pest beetle populations. A warmer climate may lead to invasion of other population-regulating parasitoids, but also new serious pest may invade. With expected temperature increases it is recommended to use trap trees both in April and in June, and trap trees should be removed within 2 months instead 1 year as described in the current standard.
1 The European spruce bark beetle Ips typographus is a damaging pest on spruce in Europe. Beetle interactions with tree species originating outside the natural range of the beetle are largely unknown and may be unpredictable because trees without a co-evolutionary history with the beetle may lack effective defences. 2 The terpenoid composition and breeding suitability for I. typographus of the historic host Norway spruce Picea abies were compared with two evolutionary naïve spruces of North American origin that are extensively planted in North-West Europe: Sitka spruce Picea sitchensis and Lutz spruce Picea glauca x lutzii. 3 The bark of all three species had a similar chemical composition and similar levels of total constitutive terpenoids, although Norway spruce had higher total induced terpenoid levels. 4 Beetles tunnelling in the three spruce species produced similar amounts of aggregation pheromone. Controlled breeding experiments showed that I. typographus could produce offspring in all three species, with a similar offspring length and weight across species. However, total offspring production was much lower in Sitka and Lutz spruce. 5 Overall, the results of the present study suggest that I. typographus will be able to colonize Sitka and Lutz spruce in European plantations and in native spruce forests in North America if introduced there.
Olfaction is the most important sensory mechanism by which many insects interact with their environment and a wind tunnel is an excellent tool to study insect chemical ecology. Insects can locate point sources in a three-dimensional environment through the sensory interaction and sophisticated behavior. The quantification of this behavior is a key element in the development of new tools for pest control and decision support. A wind tunnel with a suitable flight section with laminar air flow, visual cues for in-flight feedback and a variety of options for the application of odors can be used to measure complex behaviour which subsequently may allow the identification of attractive or repellent odors, insect flight characteristics, visual-odor interactions and interactions between attractants and odors lingering as background odors in the environment. A wind tunnel holds the advantage of studying the odor mediated behavioural repertoire of an insect in a laboratory setting. Behavioural measures in a controlled setting provide the link between the insect physiology and field application. A wind tunnel must be a flexible tool and should easily support the changes to setup and hardware to fit different research questions. The major disadvantage to the wind tunnel setup described here, is the clean odor background which necessitates special attention when developing a synthetic volatile blend for field application.
In temperate forests, red wood ants (Formica aquilonia) are considered ecosystem engineers affecting ecosystem properties and functions. Possible effects of F. aquilonia ants on species communities of invertebrates and plants were studied in the pine-dominated Geitaknottane forest reserve, Norway. Species richness of carabids, lichens and epiphytes (tree-living lichens and bryophytes) was negatively affected by ant mound density. Species of all groups, except for lichens and snails, were affected either positively or negatively by ant presence. Food availability and interference competition are plausible explanations of decreased species richness and negative species associations in carabids; while collecting, foraging and changed chemical environment may explain decreased species richness in lichens and epiphytes. Thirteen out of 15 plant and invertebrate species were weakly associated with ant mound density. Associations of only two species (Carabus violaceus and Drusilla canaliculata) were negative, while Pella humeralis and Agroeca proxima were associated positively and very strongly with ant mounds. Positive associations with ants of those invertebrates may be a response to excessive abundance of food and chemical mimicry.
Mulching of soil beds of strawberry fields is usually done with polyethylene film in southern Minas Gerais state, Brazil. This material is relatively expensive and difficult to discard after use. In some countries, mulching is done with the use of organic material that could have an advantage over the use of plastic for its easier degradation after use, and for favoring edaphic beneficial organisms. Predatory mites (especially Gamasina, Mesostigmata) may be abundant in the soil and could conceivably move to the soil surface and onto the short-growing strawberry plants at night, helping in the control or pest arthropods. The two-spotted spider mite, Tetranychus urticae Koch, is considered an important strawberry pest in that region, where the fungus Neozygites floridana (Weiser and Muma) has been found to infect it. Different mulching types could affect the incidence of this pathogen. Dehydrated coffee husk and pulp (DCHP) is a byproduct readily available in southern Minas Gerais, where could be used as organic mulching in strawberry beds. The temporary contact of that material with the soil of a patch of natural vegetation could facilitate its colonization by edaphic predatory mites helpful in the control of strawberry pests. The objective of this work was to study the effect of mulching type on the population dynamics of the two-spotted spider mite, associate mites and N. floridana, in a greenhouse and in the field. The use of DCHP increased the number of edaphic Gamasina on strawberry plants—Proctolaelaps pygmaeus (Müller) (Melicharidae) and Blattisocius dentriticus (Berlese) (Blattisociidae) were observed on strawberry leaflets, mainly in nocturnal samplings, indicating their possible daily migration from soil to plants. Lower levels of two-spotted spider mite occurred on plants from pots or soil beds mulched with DCHP instead of polyethylene film, possibly because of the slightly higher levels of mites of the family Phytoseiidae and infection by N. floridana. Adding DCHP onto the floor of natural vegetation did not result in higher diversity or levels of gamasine mites on DCHP. Complementary studies should be conducted to find ways to increase diversity and density of those organisms in strawberry beds, in an attempt to improve biological control of strawberry pests. The decision to use DCHP for mulching should also take into account other factors such as strawberry yield, costs and efficiency of weed management, to be evaluated in subsequent studies.
Neozygites floridana is a pathogenic fungus and natural enemy of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), which is an important polyphagous plant pest. The aim of this study was to reveal and predict what combination of temperature, relative humidity (RH), and time that enables and promotes primary conidia production and capilliconidia formation in N. floridana (Brazilian isolate ESALQ 1420), in both a detached leaf assay mimicking climatic conditions in the leaf boundary layer and in a semi-field experiment. In the detached leaf assay, a significant number of conidia were produced at 90% RH but the highest total number of primary conidia and proportion of capilliconidia was found at 95 and 100% RH at 25 °C. Positive temperature and RH effects were observed and conidia production was highest in the 8 to 12 h interval. The semi-field experiment showed that for a >90% probability of N. floridana sporulation, a minimum of 6 h with RH >90% and 10 h with temperatures >21 °C, or 6 h with temperatures >21 °C and 15 h with RH >90% was needed. Our study identified suitable conditions for primary- and capilliconidia production in this Brazilian N. floridana isolate. This information provides an important base for building models of a Decision Support System (DSS) where this natural enemy may be used as a tool in Integrated Pest Management (IPM) and a base for developing in vivo production systems of N. floridana.
We investigated the ability of the fungal entomopathogen Beauveria bassiana strain GHA to endophytically colonize sugarcane (Saccharum officinarum) and its impact on plant growth. We used foliar spray, stem injection, and soil drench inoculation methods. All three inoculation methods resulted in B. bassiana colonizing sugarcane tissues. Extent of fungal colonization differed significantly with inoculation method (χ2 = 20.112, d. f. = 2, p < 0.001), and stem injection showed the highest colonization level followed by foliar spray and root drench. Extent of fungal colonization differed significantly with plant part (χ2 = 33.072, d. f. = 5, p < 0.001); stem injection resulted in B. bassiana colonization of the stem and to some extent leaves; foliar spray resulted in colonization of leaves and to some extent, the stem; and soil drench resulted in colonization of roots and to some extent the stem. Irrespective of inoculation method, B. bassiana colonization was 2.8 times lower at 14–16 d post inoculation (DPI) than at 7–10 DPI (p = 0.020). Spraying leaves and drenching the soil with B. bassiana significantly (p = 0.01) enhanced numbers of sett roots. This study demonstrates for the first time that B. bassiana can endophytically colonize sugarcane plants and enhance the root sett and it provides a starting point for exploring the use of this fungus as an endophyte in management of sugarcane pests.
Blue and yellow sticky traps equipped with blue light emitting diodes (LEDs) were evaluated for their attractiveness to the western flower thrips (Frankliniella occidentalis Pergande) and compared to similar traps without light in two greenhouses with commercial production of either mixed herbs or Alstroemeria cut flowers. Blue traps were more attractive to F. occidentalis than the yellow traps in both crops, regardless of whether they were equipped with light or not. In herbs, the blue light equipped traps caught 1.7 to 2.5 times more thrips compared to blue traps without light, and 1.7 to 3.0 times more thrips than yellow traps with light. Blue light on both blue and yellow traps increased thrips catches in one out of two experiments in Alstroemeria. The blue light equipped traps caught 3.4 and 4.0 times more thrips than blue traps without light in coloured and white Alstroemeria cultivars, respectively, whereas yellow light equipped traps increased thrips catches 4.5 times compared to yellow traps without light in both coloured and white cultivars. The yellow light equipped traps caught, however, only equal to or only slightly more thrips than blue traps without light, and caught fewer thrips than the light equipped blue traps. The relative trapping efficiency of the different combinations of trap colour and light varied with experiment, crop and Alstroemeria cultivars. This suggests that factors other than merely the addition of light influenced the thrips' phototactic response to the traps. Such factors could be differences in the relative strength of the competition between attractive signals from traps and plants between the two crops and Alstroemeria cultivars, thrips density, seasonal lighting conditions or different pest management strategies and other operational procedures in the greenhouses. The light from the traps did not increase the thrips population on the plants below the traps. The implications of the results for thrips control and suggestions for further studies are discussed.
Most horticultural crops are attacked by more than one insect pest. As broad-spectrum chemical control options are becoming increasingly restricted, there is a need to develop novel control methods. Semiochemical attrac- tants are available for three important horticultural pests, strawberry blossom weevil, Anthonomus rubi Herbst (Coleoptera: Curculionidae), European tarnished plant bug, Lygus rugulipennis Poppius (Hemiptera: Miridae) and raspberry beetle, Byturus tomentosus deGeer (Coleoptera: Byturidae). Traps targeting more than one pest species would be more practical and economical for both monitoring and mass trapping than traps for single-species. In this study we aimed to (1) improve the effectiveness of existing traps for insect pests in strawberry and raspberry crops by increasing catches of each species, and (2) test if attractants for two unrelated pest species could be combined to capture both in the same trap without decreasing the total catches. Field tests were carried out in four European countries and different combinations of semiochemicals were compared. A volatile from straw- berry flowers, 1,4 dimethoxybenzene (DMB), increased the attractiveness of the aggregation pheromone to both sexes of A. rubi. The host-plant volatile, phenylacetaldehyde (PAA), increased the attraction of female L. rugu- lipennis to the sex pheromone, and, in strawberry, there was some evidence that adding DMB increased catches further. Traps baited with the aggregation pheromone of A. rubi, DMB, the sex pheromone of L. rugulipennis and PAA attracted both target species to the same trap with no significant difference in catches compared to those single-species traps. In raspberry, catches in traps baited with a combination of A. rubi aggregation pheromone, DMB and the commercially available lure for B. tomentosus, based on raspberry flower volatiles, were similar to those in single-species traps. In both crops the efficiency of the traps still needs improvement, but the multi- species traps are adequate for monitoring and should not lead to confusion for the user as the target species are easy to distinguish from each other.
In regions with short growth seasons, it is of great importance to use potato (Solanum tuberosum L.) seed tubers with a high growth vigour and a short growth cycle. Such qualities may be obtained by treatments advancing the physiological age of the seed tubers. In this study, we have exposed tubers from four cultivars to various combinations of temperature and light conditions (greensprouting) for 3–7 months in controlled climate. Subsequent sprout quality, seed tuber health and performance were studied in laboratory, greenhouse and field trials. Satisfactory short, sturdy and leafy sprouts were produced even after 7 months storage at 15 °C under light exposure. An assay of black scurf (Rhizoctonia solani) on the tuber skin showed that light exposure significantly reduced the occurrence compared with dark-stored tubers, while the average effect of storage temperatures was insignificant. In general, green-sprouting advanced emergence and plant growth by 1–2 weeks, and showed early tuber initiation and growth, compared to untreated material. Yields, 107 days after planting in the field trial, did not deviate significantly from untreated tubers. However, plant development at harvest was in accordance with general responses to physiological ageing of potato seed tubers, i.e. still tall and immature plants from untreated tubers, and short and mature plants from aged tubers. Results demonstrated the possibility of successful long-term storage of potato seed tubers in light at elevated temperatures and a potential for earlier harvests and higher early yields from such treatments.
Bark beetles are among the most devastating biotic agents affecting forests globally and several species are expected to be favored by climate change. Given the potential interactions of insect outbreaks with other biotic and abiotic disturbances, and the potentially strong impact of changing disturbance regimes on forest resources, investigating climatic drivers of destructive bark beetle outbreaks is of paramount importance. We analyzed 17 time-series of the amount of wood damaged by Ips typographus, the most destructive pest of Norway spruce forests, collected across 8 European countries in the last three decades. We aimed to quantify the relative importance of key climate drivers in explaining timber loss dynamics, also testing for possible synergistic effects. Local outbreaks shared the same drivers, including increasing summer rainfall deficit and warm temperatures. Large availability of storm-felled trees in the previous year was also strongly related to an increase in timber loss, likely by providing an alternative source of breeding material. We did not find any positive synergy among outbreak drivers. On the contrary, the occurrence of large storms reduced the positive effect of warming temperatures and rainfall deficit. The large surplus of breeding material likely boosted I. typographus population size above the density threshold required to colonize and kill healthy trees irrespective of other climate triggers. Importantly, we found strong negative density dependence in I. typographus that may provide a mechanism for population decline after population eruptions. Generality in the effects of complex climatic events across different geographical areas suggests that the large-scale drivers can be used as early warning indicators of increasing local outbreak probability.
Angiostoma norvegicum n. sp. (Angiostomatidae) is described from the oesophagus, crop and the buccal mass of five species of slugs of the family Arionidae, Arion vulgaris (Moquin-Tandon), Arion ater (L.), Arion fasciatus (Nilsson), Arion fuscus (Müller) and Arion rufus/Arion ater hybrid), collected throughout Norway. Angiostoma norvegicum n. sp. was found parasitising arionids at seven of the 30 sample sites examined (23.3%), and 9.9% of all Arion spp. were infected with this nematode. The new species is characterised by its large size (4.0–8.6 mm long) and in having: lateral alae; 6 + 6 papillae at the cephalic end; a large circular mouth aperture; a spacious stoma; a pharyngeal basal bulb without valvular apparatus; an excretory pore near the base of bulb; a distal part of posterior ovary always outstretched; an anterior ovary distally nearly always outstretched; a vulva situated anterior to mid-body; long, nearly straight spicules and a small gubernaculum; three circumcloacal papillae and caudal genital papillae (GP) arranged in a pattern 1+2/3+3 with GP 5 and GP 8 opened on dorsal side of narrow bursa not reaching tail tip; short conical tails in both sexes with tips supplied by 4 short, unequal denticles. Morphologically, A. norvegicum n. sp. is similar to Angiostoma limacis Dujardin, 1845, which diagnostic characteristics are given based on examination of specimens from Norway and the UK. Conversely, the phylogenetic analyses based on D2D3 large subunit (LSU) rRNA gene sequences performed in the present study did not support the morphological affinity of these two species. Phylogenetic analyses demonstrated that although Angiostoma spp. cluster together, A. norvegicum n. sp. forms a tight monophyletic clade with the milacid nematode parasites Angiostoma margaretae Ross, Malan & Ivanova, 2011 and Angiostoma milacis Ivanova & Wilson, 2009.
Despite global deforestation some regions, such as Europe, are currently experiencing rapid reforestation. Some of this is unintended woodland encroachment onto farmland as a result of reduced livestock pasture management. Our aim was to determine the likely impacts of this on exposure to ticks and tickborne disease risk for sheep in Norway, a country experiencing ecosystem changes through rapid woodland encroachment as well as increases in abundance and distribution of Ixodes ricinus ticks and tick-borne disease incidence. We conducted surveys of I. ricinus ticks on ground vegetation using cloth lure transects and counts of ticks biting lambs on spring pastures, where lambs are exposed to infection with Anaplasma phagocytophilum, the causative agent of tick-borne fever in livestock. Pastures had higher densities of I. ricinus ticks on the ground vegetation and more ticks biting lambs if there was more tree cover in or adjacent to pastures. Importantly, there was a close correlation between questing tick density on pastures and counts of ticks biting lambs on the same pasture, indicating that cloth lure transects are a good proxy of risk to livestock of tick exposure and tick-borne disease. These findings can inform policy on environmental tick control measures such as habitat management, choice of livestock grazing area and off-host application of tick control agents.
Herbivorous insects use olfactory cues to locate their host plant within a complex olfactory landscape. One such example is the European grapevine moth Lobesia botrana, a key pest of the grape in the Palearctic region, which recently expanded both its geographical and host plant range. Previous studies have showed that a synthetic blend of the three terpenoids, (E)-β-caryophyllene, (E)-β-farnesene and (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), was as attractive for the moth as the complete grape odour profile in laboratory conditions. The same studies also showed that the specific ratio of these compounds in the grape bouquet was crucial because a percentage variation in any of the three volatiles resulted in almost complete inhibition of the blend's attractiveness. Here, we report on the creation of stable grapevine transgenic lines, with modified (E)-β-caryophyllene and (E)-β-farnesene emission and thus with an altered ratio compared to the original plants. When headspace collections from these plants were tested in wind tunnel behavioural assays, they were less attractive than control extracts. This result was confirmed by testing synthetic blends imitating the ratio found on natural and transformed plants, as well as by testing the plants themselves. With this evidence, we suggest that a strategy based on volatile ratio modification may also interfere with the host-finding behaviour of L. botrana in the field, creating avenues for new pest control methods.
Fields experiments were conducted during two growing seasons (2010–2011 and 2012–2013) at three seeding dates to identify stink bug (Hemiptera: Pentatomidae) species and to determine their seasonal population density fluctuation and damage caused to three common bean (Phaseolus vulgaris L.) cultivars “Ica Pijao,” “Cubacueto 25–9,” and “Chévere.” Stink bug species observed were Nezara viridula (L.), Piezodorus guildinii (Westwood), Chinavia rolstoni (Rolston), Chinavia marginatum (Palisot de Beauvois), and Euschistus sp. The most prevalent species was N. viridula in both seasons. The largest number of stink bugs was found in beans seeded at the first (mid September) and third (beginning of January) seeding dates. Population peaked at BBCH 75 with 1.75, 0.43, and 1.25 stink bugs/10 plants in 2010–2011 and with 2.67, 0.45, and 1.3 stink bugs/10 plants in 2012–2013 in the fields seeded the first, second, and third seeding dates, respectively. The lowest numbers of stink bugs were found in beans seeded at the second (mid November) seeding date. A significant negative correlation between relative humidity and number of stink bugs was found in 2010–2011, and a similar tendency was observed in 2012–2013. The highest seed and pod damage levels occurred in cv. “Chévere” and the lowest in cv. “ICA Pijao” during both seasons. Results suggest that cv. “ICA Pijao” and the second (mid November) seeding date is the best choice to reduce stink bug damage.
The aim of this study was to evaluate the natural occurrence of Beauveria spp. in soil, from infections in the stink bug Piezodorus guildinii, an important pest of common bean (Phaseolus vulgaris) and as endophytes in bean plant tissue. Twelve conventional and 12 organic common bean fields in the Villa Clara province, Cuba were sampled from September 2014 to April 2015. One hundred and fifty Beauveria isolates were obtained from soil samples, bean plant parts and stink bugs. The overall frequency of occurrence of Beauveria isolates in conventional fields (8.4%) was significantly lower than that in organic fields (23.6%). Beauveria were also obtained significantly more frequently from bean roots in organic fields (15.0%) compared to bean roots in conventional fields (3.3%). DNA sequencing of the intergenic Bloc region was performed for Beauveria species identification. All isolates where characterized as Beauveria bassiana (Balsamo-Crivelli) Vuillemin, and clustered with isolates of neotropical origin previously described as AFNEO_1. The Cuban B. bassiana isolates formed five clusters in the phylogeny. Isolates of two clusters originated from all four locations, organic and conventional fields, as well as soil, plants and stink bugs. Organic fields contained isolates of all five clusters while conventional fields only harbored isolates of the two most frequent ones. Mating type PCR assays revealed that mating type distribution was skewed, with MAT1/MAT2 proportion of 146/4, indicating limited potential for recombination. The present study is the first to report of B. bassiana as a naturally occurring endophyte in common bean. Further, it shows that B. bassiana occurs naturally in diverse environments of common bean fields, and constitutes a potential reservoir of natural enemies against pest insects particularly in organic fields.
Strawberry blossom weevil (SBW), Anthonomus rubi Herbst (Coleoptera: Curculionidae) and European tarnished plant bug (ETB), Lygus rugulipennis Poppius (Hetereoptera: Miridae), cause significant damage to strawberry and raspberry crops. Using the SBW aggregation pheromone and ETB sex pheromone we optimized and tested a single trap for both species. A series of field experiments in crops and seminatural habitats in five European countries tested capture of the target pests and the ability to avoid captures of beneficial arthropods. A Unitrap containing a trapping agent of water and detergent and with a cross vane was more efficient at capturing both species compared to traps which incorporated glue as a trapping agent. Adding a green cross vane deterred attraction of non-pest species such as bees, but did not compromise catches of the target pests. The trap caught higher numbers of ETB and SBW if deployed at ground level and although a cross vane was not important for catches of ETB it was needed for significant captures of SBW. The potential for mass trapping SBWand ETB simultaneously in soft fruit crops is discussed including potential improvements to make this more effective and economic to deploy.
Liriomyza huidobrensis (Blanchard) is native to South America but has expanded its range and invaded many regions of the world, primarily on flowers and to a lesser extent on horticultural product shipments. As a result of initial invasion into an area, damage caused is usually significant but not necessarily sustained. Currently, it is an economic pest in selected native and invaded regions of the world. Adults cause damage by puncturing abaxial and adaxial leaf surfaces for feeding and egg laying sites. Larvae mine the leaf parenchyma tissues which can lead to leaves drying and wilting. We have recorded 365 host plant species from 49 families and more than 106 parasitoid species. In a subset of the Argentinian data, we found that parasitoid community composition attacking L. huidobrensis differs significantly in cultivated and uncultivated plants. No such effect was found at the world level, probably due to differences in collection methods in the different references. We review the existing knowledge as a means of setting the context for new and unpublished data. The main objective is to provide an update of widely dispersed and until now unpublished data, evaluate dispersion of the leafminer and management strategies in different regions of the world, and highlight the need to consider the possible effects of climate change on further regional invasions or expansions.
BACKGROUND Broccoli (Brassica oleracea L. var. italica) is a popular vegetable grown at a wide range of latitudes. Plants were grown in 2009–2011 in pots with standardized soil, irrigation and nutrient supply under natural temperature and light conditions at four locations (42–70° N). A descriptive sensory analysis of broccoli florets was performed by a trained panel to examine any differences along the latitudinal gradient for 30 attributes within appearance, odour, taste/flavour and texture. RESULTS Average results over three summer seasons in Germany, southern Norway and northern Norway showed that the northernmost location with low temperatures and long days had highest scores for bud coarseness and uniform colour, while broccoli from the German location, with high temperatures and shorter days, had highest intensity of colour hue, whiteness, bitter taste, cabbage flavour, stale flavour and watery flavour. Results from two autumn seasons at the fourth location (42° N, Spain), with low temperatures and short days, tended toward results from the two northernmost locations, with an exception for most texture attributes. CONCLUSION Results clearly demonstrate that temperature and light conditions related to latitude and season affect the sensory quality of broccoli florets. Results may be used in marketing special quality regional or seasonal products. © 2016 Society of Chemical Industry
BACKGROUND Vegetable growers in Arctic areas must increasingly rely on market strategies based on regional origin and product quality. Swede roots (rutabaga) were grown in a phytotron to investigate the effect of high latitude light conditions on sensory quality and some health and sensory-related compounds. Experimental treatments included modifications of 24 h natural day length (69° 39' N) by moving plants at daily intervals to dark chambers with either no light, fluorescent growth light and/or low intensity photoperiod extension. RESULTS Shortening the photosynthetic light period to 12 h produced smaller roots than 15.7 h and 18 h, with highest scores for bitter and sulfur taste, and lowest scores for sweetness, acidic taste and fibrousness. The photoperiod in combination with the photosynthetic light period also had an influence on glucosinolate (GLS) contents, with lowest concentrations in 24 h natural light and highest in 12 h natural light. Concentrations of vitamin C, glucose, fructose and sucrose were not significantly influenced by any of the treatments. CONCLUSION High latitude light conditions, with long photosynthetic light periods and 24 h photoperiod, can enhance sweet/less bitter taste and reduce GLS contents in swede roots, compared to growth under short day conditions. This influence of light conditions on eating quality may benefit marketing of regional products from high latitudes. © 2017 Society of Chemical Industry
Pre-sprouting of potato seed tubers (Solanum tuberosum L.) in light (greensprouting) is an established practice in short growing seasons to speed up plant development. Light exposure secures short and robust sprouts for mechanical planting. In 2014–2015, different pre-sprouting treatments were investigated, including different daily durations of light exposure during 6 to 12 weeks at 10 °C in controlled environments. The effects on sprout growth, early growth vigour and field performance in four cultivars were assessed in the greenhouse and in the field. Results indicated that the light treatments involving 8, 16 and 24 h light exposure per day all strongly inhibited sprout growth, with only minor differences between treatments. Compared to untreated tubers, within all cultivars, emergence and early plant growth was clearly and similarly accelerated by all light treatments. At harvest, cultivars were differently affected by the pre-sprouting treatments with regard to haulm senescence (greenness), tuber DM and total yield, and the latest cultivars seemed to benefit more from green-sprouting than the earliest. Different daily durations of light exposure during green-sprouting had a largely similar impact on seed tuber performance in all cultivars. Dark-sprouted tubers (de-sprouted before planting) performed largely similar to control tubers from 4 °C storage. Results demonstrate a potential for shorter daily light exposure during greensprouting with less energy use and heating problems.
A new subspecies of the European cerambycid Saperda populnea (Linnaeus, 1758) is described: Saperda populnea lapponica ssp. n. based on specimens from Scandinavia. The male genitalia characters were examined and found to provide support for this separation, as well as differences in morphology, geographical distribution and bionomy. The preferred host tree for the nominate subspecies S. populnea populnea is Populus tremula L., whereas S. populnea lapponica ssp. n. is considered to be monophagous on Salix lapponum L. DNA sequence data of mitochondrial cytochrome oxidase subunit I (COI) was generated from Scandinavian specimens of S. populnea populnea and specimens representing S. populnea lapponica ssp. n. The two subspecies were not reciprocally monophyletic and genetic distances in COI were small. All synonyms of S. populnea populnea have been considered, and species similar to S. populnea populnea have been examined, and not found to be related to S. populnea lapponica ssp. n. A male lectotype has been designated for each of the two following synonyms: Cerambyx decempunctatus De Geer, 1775, and Saperda salicis Zetterstedt, 1818. The synonymised species from Asia, S. balsamifera (Motshulsky, 1860), is elevated to subspecies: S. populnea balsamifera stat. n. We end with a discussion on the definition of subspecies under the unified species concept.
We present a revised checklist of harvestmen (Opiliones) covering all the Nordic countries, including Iceland and the Faroe Islands. Altogether 31 species from 18 genera and four families are currently known, of which 23 are from Norway, 21 from Sweden, 17 from Finland, 25 from Denmark, five from the Faroe Islands and four from Iceland. Five species are documented for the first time in Norway: Lacinius dentiger (C. L. Koch, 1847), Lacinius horridus (Panzer, 1794), Opilio saxatilis C. L. Koch, 1839, Leiobunum blackwalli Meade, 1861 and Leiobunum limbatum L. Koch, 1861.
This contribution demonstrates an example of experimental automatic image analysis to detect spores prepared on microscope slides derived from trapping. The application is to monitor aerial spore counts of the entomopathogenic fungus Pandora neoaphidis which may serve as a biological control agent for aphids. Automatic detection of such spores can therefore play a role in plant protection. The present approach for such detection is a modification of traditional manual microscopy of prepared slides, where autonomous image recording precedes computerised image analysis. The purpose of the present image analysis is to support human visual inspection of imagery data – not to replace it. The workflow has three components: • Preparation of slides for microscopy. • Image recording. • Computerised image processing where the initial part is, as usual, segmentation depending on the actual data product. Then comes identification of blobs, calculation of principal axes of blobs, symmetry operations and projection on a three parameter egg shape space.
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Swede is a root vegetable grown under a range of growth conditions that may influence the product quality. The objective of this controlled climate study was to find the effect of growth temperature on sensory quality and the contents of glucosinolates, vitamin C and soluble sugars. High temperature (21 °C) enhanced the intensities of sensory attributes like pungent odour, bitterness, astringency and fibrousness, while low temperature (9 °C) was associated with acidic odour, sweet taste, crispiness and juiciness. Ten glucosinolates were quantified, with progoitrin as the dominant component followed by glucoberteroin, both with highest content at 21 °C. Vitamin C also had its highest content at 21 °C, while the total sugar content was lowest at this temperature. In conclusion, the study demonstrated clear effects of growth temperature on sensory quality and some chemical properties of swede and indicated a good eating quality of swedes grown at low temperatures.
In the absence of effective control measures, the strawberry blossom weevil (Anthonomus rubi) (SBW) and the raspberry beetle (Byturus tomentosus) (RB) cause large (10 - >80%) losses in yield and quality in organically grown raspberry. Attractive lures for both pests were combined into a single multitrap for the economical management of both of these pests at the same time. This is one of the first approaches to pest management of non-lepidopteran insect pests of horticultural crops using semiochemicals in the EU, and probably the first to target multiple species from different insect orders. The aim is to develop optimized lures and cost-effective trap designs for mass trapping and to determine the optimum density and spatial and temporal patterns of deployment of the traps for controlling these pests by mass trapping. The combination between an aggregation pheromone that attracts Anthonomus rubi and a raspberry flower volatile that attracts Byturus tomentosus seems to be the best combination.
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Herbivory by insects and mites on physic nut (Jatropha curcas L.) seedlings was investigated and compared with irrigation in the semi-arid Sahelian Niger, utilizing a randomized complete block design experiment. Three water treatment protocols were applied and the types of damage were recorded. Less than 5% of the seedlings died during the 10-month trial period with sap suckers causing the most damage on the surviving plants. Plants with high production of biomass and leaf cover (foliage) were most strongly positively correlated with irrigation and were also the plants that endured the highest degree of herbivory. The low dieback may indicate that defence mechanisms counteract seedling herbivory and that drought-stressed plants invest more in their defence mechanism system than vital plants.
In this chapter we will focus on the tick Ixodes ricinus, with its main geographical distribution in Europe. It is known to transmit a variety of pathogens, among them Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis. Tick population control is one of the measures to reduce the incidence of tick-borne diseases. Due to non-target effects of chemical acaricides, acquired resistance against chemical acaricides and increased regulations, there is a demand for sustainable control measures that may be used in integrated vector management (IVM) of ticks. This chapter describes and evaluates the present knowledge on biological control of I. ricinus as an alternative to the use of chemical acaricides. Biological control makes use of living organisms (e.g. fungi, bacteria, nematodes, invertebrate predators, parasitoids) to suppress a pest population. The natural occurrence of these organisms in I. ricinus and the use of these organisms as biological control agents against I. ricinus are reviewed. Entomopathogenic fungi (Beauveria and Metarhizium spp.) are the most commonly used biocontrol agents against ticks. A variety of nematode species are also shown to be effective against different tick species, but the knowledge on the operational use of invertebrate predators and parasitoids to control ticks is limited. We conclude that there are several candidates for the biological control of ticks, but that the knowledge on the natural occurrence and efficacy of these to control I. ricinus populations is very limited. There is, therefore, a need of more studies on naturally occurring enemies of I. ricinus to be able to suggest possible biocontrol candidates. These candidates should be tested in controlled laboratory and field studies with the aim to develop elegant, precise and effective biocontrol strategies for the control of I. ricinus that may be used alone or in combination with other control strategies in IVM.
Tick-borne diseases, such as anaplasmosis and babesiosis, are of major concern for Norwegian sheep farmers. Ticks can be controlled on and off the host, usually with the long-term, high-rotation use of chemicals. Fungal pathogens, predatory mites and ants are thought to be important tick killers in nature. However, the prevalence and diversity of predatory mites in tick habitats has barely been evaluated. It is known that most soil mite species of the cohort Gamasina (order Mesostigmata) are predators. Until now, 220 mesostigmatid species have been reported from Norway, most of them belonging to the Gamasina. One of the first recommended steps in a biological control program involves the determination of the fauna in the pest habitat. The objective of this study was to determine the groups of gamasines co-occurring with I. ricinus in sheep grazing areas in Isfjorden and Tingvoll in Western Norway. A total of 2,900 gamasines of 12 families was collected. The most numerous families were Parasitidae (46.9%) and Veigaiidae (25.7%), whereas the most diverse families were Laelapidae, Macrochelidae, Parasitidae and Zerconidae. Our results showed that the tick density was significantly related only to locality, elevation and rainfall. Differences in the prevailing environmental conditions resulted in more outstanding differences between Gamasina abundances than diversities. Based on our present knowledge of the potential of different gamasine groups as biological control agents, the results suggested that laelapid mites should be among the priority groups to be further evaluated for their role in the natural control of I. ricinus in Norway.
Background. The beneficial fungus Neozygites floridana kills the two-spotted spider mite Tetranychus urticae, which is a serious polyphagous plant pest worldwide. Outbreaks of spider mites in strawberry and soybean have been associated with pesticide applications. Pesticides may affect N. floridana and consequently the natural control of T. urticae. N. floridana is a fungus difficult to grow in artificial media, and for this reason, very few studies have been conducted with this fungus, especially regarding the impact of pesticides. The aim of this study was to conduct a laboratory experiment to evaluate the effect of pesticides used in strawberry and soybean crops on N. floridana. Results. Among the pesticides used in strawberry, the fungicides sulfur and cyprodinil + fludioxonil completely inhibited both the sporulation and conidial germination of N. floridana. The fungicide fluazinam affected N. floridana drastically. The application of the fungicide tebuconazole and the insecticides fenpropathrin and abamectin resulted in a less pronounced negative effect on N. floridana. Except for epoxiconazole and cyproconazole, all tested fungicides used in soybean resulted in a complete inhibition of N. floridana. Among the three insecticides used in soybean, lambda-cyhalothrin and deltamethrin resulted in a significant inhibition of N. floridana. Conclusion. The insecticides/ acaricides abamectin and lambda-cyhalothrin at half concentrations and fenpropathrin and permethrin and the fungicide tebuconazole at the recommended concentrations resulted in the lowest impact on N. floridana. The fungicides with the active ingredients sulfur, cyprodinil + fludioxonil, azoxystrobin, azoxystrobin + cyproconazole, trifloxystrobin + tebuconazole and pyraclostrobin + epoxiconazole negatively affected N. floridana. © 2015 Society of Chemical Industry
A controlled climatic chamber microcosm experiment was conducted to examine how light affects the hourly sporulation pattern of the beneficial mite pathogenic fungus Neozygites floridana during a 24 h cyclus over a period of eight consecutive days. This was done by inoculating two-spotted spider mites (Tetranychus urticae) with N. floridana and placing them on strawberry plants for death and sporulation. Spore (primary conidia) discharge was observed by using a spore trap. Two light regimes were tested: Plant growth light of 150 μmol m−2 s−1 for 12 h supplied by high pressure sodium lamps (HPS), followed by either; (i) 4 h of 50 μmol m−2 s−1 light with similar HPS lamps followed by 8 h darkness (full HPS light + reduced HPS light + darkness) or (ii) 4 h of 50 μmol m−2 s−1 red light followed by 8 h darkness (full HPS light + red light + darkness). A clear difference in hourly primary conidia discharge pattern between the two different light treatments was seen and a significant interaction effect between light treatment and hour in day during the 24 h cycle was observed. The primary conidia discharge peak for treatment (ii) that included red light was mainly reached within the red light hours (19:00–23:00) and the dark hours (23:00–07:00). The primary conidia discharge peak for treatment (i) with HPS light only was mainly reached within the dark hours (23:00–07:00).
The purpose of this study is to increase the basic understanding of outbreak dynamics in order to improve the management of bark beetle outbreaks. The spruce bark beetle Ips typographus is a major disturbance agent of European forests and is the continent’s most economically and environmentally damaging bark beetle. Outbreaks of the spruce bark beetle are often triggered by large windfall episodes, and we have utilized a unique opportunity to study a Slovakian outbreak where little salvage logging was performed in some areas after a 2.5 million m3 storm-felling in 2004. Our analyses focused on the first five years after the windfall, and we used a combination of empirical data and simulation models to understand the spatial patterns of beetle-killed forest patches developing during the outbreak. The univoltine beetle population used an increasing proportion of the windfelled trees during the two first seasons after the storm, but from the third season onwards our comparisons of inter-patch distance distributions indicated a transition from beetle production largely in windfall areas to a self-sustaining outbreak with infestation patches developing independently of the windthrows. The size of new infestation patches formed after this transition was modeled as a function of beetle pressure, estimated by the proportion of a circle area surrounding new patches that was covered by infestation patches the previous year. Our model results of patch size distribution did not correspond well with the empirical data if patch formation was modeled as a pure dispersal–diffusion process. However, beetle aggregation on individual trees appears to be important for patch development, since good correspondence with empirical data was found when beetle aggregation was incorporated in the modeled dispersal process. The strength of correspondence between the beetle aggregation model and the empirical data varied with the density of aggregation trees in the modeled landscape, and reached a maximum of 83% for a density of three aggregation trees per infestation patch. Our results suggest that efficient removal of windfelled trees up until the start of the second summer after a major windfall is important to avoid a transition into a patch-driven bark beetle outbreak that is very difficult to manage. Our results also indicate that the outcome of a patch-driven outbreak is difficult to predict, since the development of new infestation patches is not a simple function of beetle pressure but is also affected by beetle behavior and local forest conditions.
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BACKGROUND Plants grown at different latitudes experience differences in light spectral composition. Broccoli (Brassica oleracea L. var italica) plants were grown in climate-controlled chambers under supplemental wavelengths (red, far-red, red + far-red or blue) from light-emitting diodes (LEDs). The light treatments were combined with two cold climate temperatures (12 and 15 °C) during broccoli head formation to investigate the effects on morphology and content of health- and sensory-related compounds: glucosinolates, flavonols, ascorbic acid and soluble sugars. RESULTS Supplemental far-red and red + far-red light led to elongated plants and the lowest total glucosinolate content in broccoli florets. The content of quercetin was highest with supplemental red light. Vitamin C was not significantly affected by the light treatments, but 12 °C gave a higher content than 15 °C. CONCLUSION The effects of supplemental red and far-red light suggest an involvement of phytochromes in the regulation of glucosinolates and flavonols. A shift in red:far-red ratio could cause changes in their content besides altering the morphology. The sugar and vitamin C content appears to be unaffected by these light conditions. Supplemental blue light had little effect on plant morphology and content of the health- and sensory related compounds.
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A survey of nematodes associated with terrestrial slugs was conducted for the first time in Norway. A total of 611 terrestrial slugs were collected from 32 sample sites. Slugs were identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. Twelve slug species were identified, representing four different slug families. Internal nematodes were identified by means of morphological analysis and the sequencing of the 18S rRNA gene. Of the sample sites studied, 62.5% were found to be positive for nematode parasites, with 18.7% of all slugs discovered being infected. Five nematode species were identified in this study: Alloionema appendiculatum, Agfa flexilis, Angiostoma limacis, Angiostoma sp. and Phasmarhabditis hermaphrodita. Of these species, only one nematode was previously undescribed (Angiostoma sp.). This is the first record of the presence of A. appendiculatum, A. flexilis and A. limacis in Norway.
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